Neutralization of sulfonation mixtures and products thereof



NEUTRALIZATION F SULFONATION MIXTURES AND PRODUCTS THEREOF William S. Little, Idaho Falls, Idaho, and Leonard M.

Wylie, Atlanta, Ga.', assignors to Tennessee Corporatron, New York, N. Y., a corporation of New York No Drawing. Application May 17, 1957 Serial No. 659,768

Claims. or. 260400) 'This invention relates to processes for the improvement of the color of neutralized sulfonated unsaturated fatty acids and more particularly to such processes in Whichthe unsaturated fattyacids contain from ten to eighteen carbon atoms and at least one double bond and are sulfonated by reaction with liquid 50, in liquid 80,.

The suffonation of unsaturated fatty acids and subsequent neutralization thereof by a suitable base to provide surface active agents is known and these surface active agents have many known useful properties such as def 25 U. S. Patent No. 2,743,288 describes processes for,

tergents and as wetting agents in the textile field.

obtaining these surface active agents and their uses. The neutralized sulfonated fatty acids obtained by procedures su'ch'v asthose described in U. S. Patent No. 2,743,288 are'yusually of a dark brown to reddish brown color. and such dark colors are undesirable for many uses.

"In the textile field, for example, such surface active agents should be as light in color as possible, preferably yellow to light straw so as not to impair the color of the textiles upon which the surface active agent is being used.

It isaccordingly the principal object of the present invention to provide novel processes for improving the color of neutralized sulfonated fatty acids in which the resulting products are of lighter color than has heretofore been obtained.

It is believed that the color of the neutralized sulfonated fatty acid develops with exposure time in the presence of a strong acid and to a somewhat lesser degree in the presence of a dilute acid and that the color formation is probably due to a reaction of the sensitive fatty acids such as oxidation thereof.

Most unexpectedly, we have found that the color of neutralized sulfonated fatty acids can be greatly improved and changed from dark brown or reddish brown to light yellow or to light straw color by a two-step neu tralization of the sulfonation mixture as will be more fully desribed hereinafter. In accordance with our twostep neutralization procedure, the aqueous solution of the fatty acid sulfonated with an S0 solution of S0 isdischarged from the S0 evaporator in known manner with the anhydrous sulfonated acid reaction mixture at a temperature of from 2550 F. and containing up to 30% by weight of S0 The anhydrous sulfonated acid may then be mixed with a suitable amount of water and enough base is added to the acid mixture to adjust the pl-I of-the mixture to within the range of approximately 14. 3 and preferably in the approximate range of 2-2.5. S0,: is stripped from the partially neutralized reaction mixture and after completion of stripping the mass is neutralized to a pH of approximately 6. The resulting neutralized sulfonated fatty acid has a light yellow color as compared to prior known colors of from dark brown to reddish brown.

. As noted above, the unsaturated fatty acid should contain from ten to cighteen carbon atoms and should con 'ice other than double bonds.

undecylenic, palmitolic, oleic, linoleic, linolenic and vaocenic.

The temperature at which the sulfonated mixture is discharged from the S0 evaporatorwill depend upon the :base which is employed in the subsequent partial neutralization step and this temperature falls usually within the range of to 50 F. The upper end of this temperature range may be employed when the base is sodium hydroxide, potassium hydroxide or sodium bisulfite and I when the base is an amine the upper limit of the temperature range may be dropped to approximately 40 For example, if the reaction to" obtain good color. mixture is heated above 40 F. before triethanolamine is added the color of the resultingproduct is appreciably 1 product and the heat of reaction distributed uniformly throughout the mixture gives better internal heat for 'novel processes and any aliphatic amine which boils at room temperature or higher is also satisfactory as a' In the partial neutralization step, the sulfonated mixture from the S0 evaporator is partially neutralized by the addition of a base to a pH range of from 1 to 4.3 and preferably in the pH range of approximately 22.5

depending upon the base which is employed. For example, if sodium bisulfite is employed as the base, higher pHs can be employed since sodium bisulfite is stable at such higher acidities, it being understood that the less stringent acid conditions give better color in the end stripping 80,.

As noted above, sodium hydroxide, potassium hydrox ide and sodium bisulfite are suitable bases for use in our base for use herein. These amines include but are not limited to aliphatic amines which boil at room tem perature or higher are also satisfactory as for use herein, These amines include but are not limited to aliphatic primary, secondary and tertiary amines including triethanolamine, monoethanolamine, diethanolamine, di-n butylamine, diethylamine, isopropylamine and 2-ethylhexylamine.

by circulating 1101l5 F. water through the reactor, jacket, a reactor temperature of .32" F. was neacl sled-.; v The reactor was opened and air pulled over the reaction The following examples are illustrative of processes in accordance with the present invention for improving the color of neutralized sulfonated fatty acids and of thenovel products thereof but should in no way be construed as defining or limiting the present concept, refer-' ence being had to the appended claims to determine the scope of this invention:

Example 1 123 pounds of an oleic acid containing 5% polyunsatu 5; rates and 8% saturated fatty acid were placed in a" closed, jacketed, agitated, gallon vessel. An SO So, solution, maintained at 14 F. or less, containing 40.13 pounds of S0 and 602 pounds of S0 was added to thereactor containing the oleic acid in 10 minutes with no i 1 external heating or cooling on the vessel. The tempera ture of the reaction mass during reaction dropped from! the ambient temperature to 14-20" F. The liquid S0 remaining after reaction was removed, condensed and stored. After. heating the reaction mass for 58 minutes tain no functional groups which will react with S0 addedin 15 minutes, controlling the height of foanidue Pate'hted Mar. 17, 1959 Fatty acids coming within the scope of the present concept'are, but are not limited to i toevolution of 50;, by therate. of addition of. sodium.

H O p cent 48.0 Oil do 4.8 Inorganic do 3.18 SO, do 0,5 Active do 43.52 Color, Gardner 9" When the S0, content of the reactionv mass. was re-- duced to about 1% before any base was added, the color of the product was about 12 on the Gardner scale.

Example 2 192.2 pounds of an oleic acid containing 5% polyunsaturates and 8% saturated fatty acid were placed in a closed, jacketed, agitated, 150 gallon vessel. An $0 -$0 solution, maintained at 14 F. or less, containing 62.64 pounds of S0 and 940 pounds of S0 was added to the reactor containing the oleic acid in 17% minutes with no external heating or cooling on the vessel.

The reaction mass temperature during reaction dropped from the ambient temperature to 14-20 F. The liquid S0 remaining after reaction was removed, condensed and stored. After heating the reaction mass for 103 minutes, by circulating 110-115 F. water through the reactor jacket, a reactor temperature of 36 F. was reached. The reactor was opened to the atmosphere and air pulled over the reaction mass to scavenge S0 being evolved. The circulating water was cut off and the jacket drained.

At. this point 90% (118.8 pounds) of the theoretical triethanolamine required for neutralization of the sulfonic acid and H SO formed was added in 13.5 minutes, controlling the height of foam rise by the addition rate. Immediately following the triethanolamine addition, 12 pounds of water to hydrolyze sulfate groups present was added in /2 minute. The temperature at completion offtriethanolamine and water addition was 182 F. Thev Oil percent.. 5.3 S0 o 0.6" H 0 o 2.0 Active do-.. 82-85 Inorganic do 7-10 Color, Gardner 10.5

When the S0 content of the reaction mass was lowered to 1-2% before any base was added, the color of thefinal product was about 15 on the Gardner scale.

Example 3 132 poundsof a tall oil fatty acid containing 48% linoleic acid, 50% oleic acid and 2% saturated fatty acids were placed in a closed, jacketed, agitated, 150 gallon vessel. An $0 -$0 solution, maintained at 14 F: or less, containing 43* pounds'of S0 and 645 pounds of S0 wasadded tothereactorcontaining thetall oil fatty acid. in. 10.7 minutes with. no external .heatingor cooling on the vessel. It was necessary to maintain a 27 at which its potential balances that applied to the contact 28 by the unit 22 as determined by the energization pressure of 14-16 p. s. i. g. on the reactor during reaction and also during evaporation of residual S0; to prevent the reaction mass from foaming to such an ex tent that the reactor and vapor lines to the S0 condenser would be completely filled and the condenser fouled. Evaporation was effected by circulating -115 Fl water in the jacket for 86 minutes until a pot temperature of 56 F. at 14 p. s. i. g. was reached. The S0, evaporated was condensed and stored for reuse. The reactor was blown down to atmospheric pressure and opened in 4 minutes. Air was pulled. over the reaction mass to scavenge S0 being evolved. The circulating water was cut off and the jacket drained.

146.57 pounds of water at 112 F. was added inv 20 minutes and the mass agitated for 3 minutes. (40.1 poundsof. 50% solution) of the theoretical sodium.

hydroxide required for neutralization of the sulfonic acid and H SO formed wasv added in 12 minutes to give 'a pH of 2. The temperature rose to F. Stripping was continued for 90 minutes using steam to maintain a temperature of -140 F. The partially neutralized. reaction mass was neutralized to a pH of 6 by adding 23.1 pounds of 50% sodium hydroxide and the'prod'uct' heated at 190-195 F. for two hours to hydrolyze any sulfated groups present.

The product analyzed as. follows:

H O percent". 46.0 'Oil do 60 S0 do 0.6" Inorganic do 1.9 Active dn 1 46.1 Color, Gardner 10.5

1 By difference.

When the S0 content of the reaction mass was re duced to 1-2% before adding any base, the color of the product was 15 on the Gardner scale.

Example 4 125 pounds of a tall oil fatty acid containing'48%- linoleic, 50% oleic and 2% saturated fatty acids were placed in a closed, jacketed, agitated, gallon vessel.

An $0 -$0 solution, maintained at 14 F. or less,.con-' taining 40.38 pounds of S0 and 606 pounds of S0 was enge S0 being evolved. The circulating water was cut off and the jacket drained. Agitation was continued for 6 minutes, at which time 90% (70.1 pounds) of the the-: oretical triethanolamine required for neutralization of the sulfonic acid and H 80, formed was added in 12.0 minutes. temperature of 162 F., while the pH was 2.5. The foam height during addition of triethanolamine wascontrolled After by varying the rate of triethanolamine addition. stirring 3.5 minutes, 7.8 pounds of water was added in 1 minute to hydrolyze sulfate groups present.

The partially neutralized mass was heated with steam for 5 hours at l90-220 F. to strip absorbed S0 The remainder of the theoretical triethanolamine plus 20% excess (total 32 pounds) was added to raise the pH of the final productto 5.8; I

The initial temperature was 35 F. and the-final The product analyzed as follows:

When the S0 content of the reaction mass was reduced to 1-2% before adding any base, the color of the product was about 17 on the Gardner color scale.

It should now be apparent to those skilled in the art that the processes herein described in every way satisfy the objective stated above and provide novel neutralized sulfonated fatty acids of improved color ranging from light yellow to light straw, which are particularly useful as surface active and wetting agents in the textile industry.

Changes in or modifications to the above described illustrative processes may now be suggested without departing from the present inventive concept. Reference should be had to the appended claims to determine the scope of this invention.

What is claimed is 1. In a process in which an unsaturated fatty acid is reacted with an $0 -$0 solution, the steps of heating the reaction mixture until it reaches a temperature in the range of approximately 25-50 F., removing S0 as evolved, adding a base to the reaction mixture until the pH of the reaction mixture is in the approximate range of from 14.3, and preferably in the approximate range of 2-2.5, continuoutly removing evolved SO, and after removal of S0 adding additional base to the stripped reaction mixture until the pH of the mixture is approximately 6.

2. In a process, the steps of reacting an unsaturated fatty acid containing -18 carbon atoms with an SO,- SO; solution, distilling ofi unreacted liquid S0,, maintaining the temperature of the reaction mixture in the range of approximately 25-50 F., removing evolved S0,, adding a base selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium bisulfite, an aliphatic primary amine, an aliphatic secondary amine and an aliphatic tertiary amine to the reaction mixture until the pH of the reaction mixture is in the approximate range of l-4.3, and preferably in the approximate range of 2-2.5, continuously removing evolved S0 and after removal of S0 adding additional base to the stripped reaction mixture until the pH of the reaction mixture is approximately 6.

3. In a process, the steps of reacting a fatty acid from the group consisting of undecylenic, palmitolic, oleic, linoleic, linolenic and vaccenic with an $0 -$0 solution, distilling of]? liquid unreacted S0 maintaining the temperature of the reaction mixture in the approximate range 25-30" F. and scavenging evolved S0 in a current of air, adding a base selected from the group consistin gof sodium hydroxide, potassium hydroxide, sodium bisulfite, triethanolamine, monoethanolamine, diethanolamine, di-n-butylamine, diethylamine, isopropylamine and Z-ethylhexylamine to the reaction mixture until the pH of the reaction mixture is in the approximate range 1-4.3, and preferably in the approximate range 2-2.5, continuously removing evolved S0 and then after removal of S0 adding additional base to the stripped reaction mixture until the pH of the reaction mixture is approximately 6.

4. A process as described in claim 3 in which the sulfonated reaction mixture before partial neutralization contains approximately 30% S0 and the neutralized sulfonated reaction mixture contains approximately .5 to .7% S0 5. A process as described in claim 3 including the step of heating the neutralized sulfonated reaction mixture with addition of necessary water to a temperature in the approximate range of -195 F. to hydrolyze sulfate groups.

References Cited in the tile of this patent UNITED STATES PATENTS 2,195,145 Crittenden Mar. 26, 1940 Hanan aTATEs PATENT @FFICE CERTIFICATE OF CORRECTlON Patent No, 2,878,271 March 17, 1959 William S Little at film It is hereby certified that error appears in the -printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 53, for des'ribem read described column 2,, line 36;, after "as" insert bases line 54;, for "80 read m SO oolumn 4;, lines 3 and 4, strike out "27 at which its potential balances that applied to the content 28 by the unit 22. as determined by the energizatiom'; column 5, line 32, for "continuoutly read. continuously 001mm. line 17, for sistin gof" read sisting of a Signed and sealed. this 11th day of August 1959b Attest:

AXLINE ROBERT C. WATSON Attesting Ofidcer Commissioner of Patents 

1. IN A PROCESS IN WHICH AN UNSATURATED FATTY ACID IS REACTED WITH AN SO2-SO3 SOLUTION, THE STEPS OF HEATING THE REACTION MIXTURE UNTIL IT REACHES A TEMPERTURE IN THE RANGE OF APPROXIMATELY 25-50*F. REMOVING SO2 AS EVOLVED, ADDING A BASE TO THE REACTION MIXTURE UNTIL THE PH OF THE REACTION MIXTURE IS IN THE APPROXIMATE RANGE OF FROM 1-4,3, AND PREDERABLY IN THE APPROXIMATE RANGE OF 2-2.5, CONTINUOUSLY REMOVING EVOLVED SO2 AND AFTER REMOVAL OF SO2 ADDING ADDITIONAL BASE TO THE STRIPPED REACTION MIXTURE UNTIL THE PH OF THE MIXTURE IS APPROXIMATELY
 6. 